title: Determination of uromodulin in human urine: influence of storage and processing.
abstract: BACKGROUND
  Uromodulin (Tamm-Horsfall protein) is the most abundant protein excreted in the urine under physiological conditions. It is exclusively produced in the kidney and secreted into the urine via proteolytic cleavage. The involvement of UMOD, the gene that encodes uromodulin, in rare autosomal dominant diseases, and its robust genome-wide association with the risk of chronic kidney disease suggest that the level of uromodulin in urine could represent a critical biomarker for kidney function. The structure of uromodulin is complex, with multiple disulfide bonds and typical domains of extracellular proteins.
  
  
  METHODS
  Thus far, the conditions influencing stability and measurement of uromodulin in human urine have not been systematically investigated, giving inconsistent results. In this study, we used a robust, in-house ELISA to characterize the conditions of sampling and storage necessary to provide a faithful dosage of uromodulin in the urine.
  
  
  RESULTS
  The levels of uromodulin in human urine were significantly affected by centrifugation and vortexing, as well as by the conditions and duration of storage.
  
  
  CONCLUSIONS
  These results validate a simple, low-cost ELISA and document the optimal conditions of processing and storage for measuring uromodulin in human urine.
authors.affiliation: Institute of Physiology, Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
authors.forename: Sonia
authors.initials: S
authors.lastname: Youhanna
authors.forename: Julien
authors.initials: J
authors.lastname: Weber
authors.forename: Viviane
authors.initials: V
authors.lastname: Beaujean
authors.forename: Bob
authors.initials: B
authors.lastname: Glaudemans
authors.forename: Jens
authors.initials: J
authors.lastname: Sobek
authors.forename: Olivier
authors.initials: O
authors.lastname: Devuyst
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D015415:Biomarkers / Q000652:urine; D002498:Centrifugation; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006073:Gout / Q000378:metabolism; D006801:Humans; D033461:Hyperuricemia / Q000378:metabolism; D007668:Kidney / Q000378:metabolism*; D007674:Kidney Diseases / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013048:Specimen Handling / Q000592:standards; D013696:Temperature; D058949:Uromodulin / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D058949:Uromodulin
keywords: ELISA; Tamm–Horsfall protein; biomarker; uromodulin-associated kidney disease